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glaze test for maria's blue, cone 6, ox. pmi may/june 03

updated wed 25 jun 03


Alisa Clausen on tue 24 jun 03

Glaze test for Maria's Blue, cone 6, ox. PMI May/June 03

Glaze tested on white midrange stoneware fired in electric oxidation to =

Credited to:

Firing ramp:
100c p/h to 600c (212f - 1112f)
150c p/h to 1100c (330f - 2012f)=20
100c p/h to 1220c (212f - 2228f)
5 min. soak
cool down max. to 800c
Hold 1 hour
Shut off kiln


43 Neph. Syenite
24 Gerstley Borate or Frit 3134 Please note this is how the recipe =
appeared in PMI article May-June 2003
19 Flint
9 Zinc Oxide
5 Kaolin

5 Rutile
1 Cobalt Carb.

Note: All raw materials are measured up or down to the nearest whole =
decimal. =20
Colorants or additives to a 100 gram test batch are measured in precent =
to the 100 gram test batch.

Substitutions: see details below for Frit 3134 and Frit 623 subbed for =


The glaze recipe with G.B. shows a glossy bluish/light green glaze with =
a lot of opalescence overall. Fluid where thickest, but did not drip.

The glaze recipe with Frit 3134 shows a similar glaze, glossy and deeper =
blues where opalescent The deeper opalescence gives the glaze, in =
general, a bluer cast. The overall color of the glaze is slightly =
deeper than the above.

The glaze recipe with Frit 623 is glossy and is overall a yellowish =
green. There is no opalescence and the color is more uniform.

Regards from Alisa in Denmark